The invention relates to a filter chamber configured between a chamber side and a membrane side of two parallel filter plates and divided through two filter cloths, the membrane sides of the two filter plates each include a membrane, an outlet, and a deviation element attached to the outlet and penetrating the membrane, wherein a suspension containing a solid substance can be inducted between the filter cloths when the filter device is closed, so that a filtrate penetrates the filter cloths on the chamber side and on the membrane side, while the solid substance is deposited in a filter cake on the filter cloths. The filtrate flows initially substantially parallel to the filter cloth towards the outlet, is deviated through the deviation element in an outflow direction perpendicular to the filter cloth, and flows out through the outlet, and wherein the filter plates are at a distance from each other when the filter device is open, so that the filter cloths with the filter cake can be removed from the filter chamber.
Filter devices are known such as shown in JP 06091111 A. As a technological background, furthermore, filter devices with said arrangement of a plurality of filter plates as plate stacks and filter chambers configured between two respective filter plates lying on top of one another or standing next to one another are known e.g. from DE 32 22 987 A1, DE 32 22 988 A1 and DE 199 05 674 C1. The filter cloth and a rubber elastic membrane are disposed in the filter chambers essentially in the respective separation plane between the filter plates, which are disposed adjacent to one another.
During operation of such filter devices, a suspension to be filtered is supplied under pressure to the filter chambers and pressed through the filter cloth. Thus, the solid content of the suspension accumulates on the filter cloth as a filter cake. The filtered suspension, from which the solid content has been purged, flows as a filtrate below the filter cloth and through the outlet and out of the filter chambers essentially without pressure.
Through loading the outlet with a washing medium, e.g. water, the filter cake can be flushed subsequently. After the filtration process is completed, the pressure medium cavity on the membrane side of the filter chamber is loaded with air as a pressure medium or e.g. with water. In turn, the filter cloth then presses the liquid out, which has remained in the filter cake. Through loading the outlet with air, the filter cake can be dried subsequently.
The membrane includes a circumferential edge bead, which lies in a groove in the filter plate enclosing the filter chamber on the membrane side during the operation of the filter device. The filter chamber and the base of the filter chamber configured in the filter plate on the membrane side essentially cover the same surface, so that the edge bead is supported on the filter plate with the filter chamber closed.
During filtration operation of the known filter device, the out flowing filtrate is deviated into the outlet through the deviation element. Thus, the filter cloth, which is pressed onto the membrane on the side of the membrane, does not penetrate the outlet configured at this location during the filtering process.
Furthermore, also the washing medium and drying air are run through the outlet into the filter chamber under pressure after the filtering is completed. The deviation element of the known filter device prevents that washing medium and drying air impact the filter cloth with high velocity perpendicular or substantially perpendicular, and that the filter cloth is substantially shot through and strongly worn overall, like in the filter devices known from the technological background, in particular by solid particles comprised of deposits in the filtrate channel and transported in the drying air.
The seal rim of the membrane extending in the membrane about the outlet and the recess configured at this location comprises a certain amount of flexibility due to its material and can be positioned only with difficulties in the known filter device in the filter plate with the required tolerance. The known filter device therefore typically has leaks at this location during operation.